Editorial: increasing burden of nonalcoholic fatty liver disease—a call to action

Non-alcoholic fatty liver disease (NAFLD) causes significant economic burden1 and impairment of health-related quality of life.2 Estes et al reported the projected burden of non-alcoholic liver disease (NAFLD) based on Markov modelling in four developed Asian countries during 2019-2030.3 Over the 12-year period, prevalent NAFLD cases would increase between 6% and 20%, while prevalent non-alcoholic steatohepatitis cases would increase between 20% and 35%. On the other hand, incident cases of decompensated cirrhosis and hepatocellular carcinoma (HCC) would increase between 65% and 100% and between 65% and 85%, respectively, while NAFLD-related mortality would increase between 75% and 100%. The increasing prevalence of NAFLD would parallel the increasing prevalence of obesity. However, as the authors have pointed out, the period of most rapid increase in obesity is over, leaving a relatively modest projected increase in the prevalence of NAFLD. On the other hand, the large pool of prevalent NAFLD cases and the progressive nature of the disease would continue to fuel increases in NAFLDrelated complications and mortality. Previously, Estes et al have used a similar model to estimate the projected burden of NAFLD in several Western countries as well as in China and Japan during 2016 to 2030.4 The projected growth for prevalent NASH cases and for incident cases of decompensated cirrhosis and HCC and NAFLD-related mortality were remarkably higher in Western countries (Table 1). This is likely due to the lag in the rise in obesity in Asia, that resulted in a lag in the development of more severe NAFLD when compared with the West.5 The progression of fibrosis by one stage takes approximately 7.1 years in patients with NASH and 14.3 years in patients with non-alcoholic fatty liver.6 Active measures to fight the increase in NAFLD and the progression of the disease are paramount to mitigate the projected increases in NAFLD-related complications and mortality. Using prevention of hepatitis B virus-related HCC as an analogy,7 preventing the development of obesity in lean individuals (ie primary prevention) would be the most important step in the fight against NAFLD. Currently, much of the effort is focused on lifestyle intervention in NAFLD patients to prevent progression (ie secondary prevention) and treatment of NAFLD-related complications (eg variceal bleeding, decompensation, HCC) to prevent recurrence or mortality (ie tertiary prevention). While clinical trials on drugs that are aimed to alter the natural history of NAFLD are actively ongoing, the potential of lifestyle intervention, which has been shown to be effective to resolve NASH and to result in fibrosis improvement,8 has not been optimised. For example, only 1.6% of biopsy-proven NASH patients in a multicentre Asian study were referred to a structured lifestyle program.9 Moreover, the responsibility of lifestyle intervention is often almost entirely shouldered by a patient, although there are multiple external factors,10 which can and should be addressed to improve the chances of success. Other than the projected burden of NAFLD, policymakers should be informed of the rate of decline in obesity and the rate of success in lifestyle intervention needed to provide a sustained positive impact, so that a clear goal can be set, in the fight against NAFLD.